Electron Configuration Gizmos

Name: Date: Student Exploration: Electron Configuration Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: atomic number, atomic radius, Aufbau principle, chemical family, diagonal rule, electron configuration, Hund’s rule, orbital, Pauli exclusion principle, period, shell, spin, subshell Prior Knowledge Questions (Do these BEFORE using the Gizmo.) 1. Elvis Perkins, a rather shy fellow, is getting on the bus shown at right. Which seat do you think he will probably sit in? Mark this seat with an “E.” 2. Marta Warren gets on the bus after Elvis. She is tired after a long day at work. Where do you think she will sit? Mark this seat with an “M.” 3. In your experience, do strangers getting on a bus like to sit with other people if there is an empty seat available? No Gizmo Warm-up Just like passengers getting on a bus, electrons orbit the nuclei of atoms in particular patterns. You will discover these patterns (and how electrons sometimes act like passengers boarding a bus) with the Electron Configuration Gizmo. To begin, check that Lithium is selected on the PERIODIC TABLE tab. 1. The atomic number is equal to the number of protons in an atom. How many protons are in a lithium atom? 3 2. A neutral atom has the same number of electrons and protons. How many electrons are in a neutral lithium atom? 3 Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

3. Select the ELECTRON CONFIGURATION tab, and check that Energy is selected. Click twice in the 1s box at lower left and once in the 2s box. Observe the atom model at right. A. What do you see? I see an atom with three electrons orbiting around B. Click Check . Is this electron configuration correct? Yes Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

7. Compare: How are the electrons in the 2p subshell similar to passengers getting on a bus? If there is an empty shell 8. Practice: In the spaces below, write and illustrate electron configurations for the next four elements: nitrogen, oxygen, fluorine, and neon. When you are finished, use the Gizmo to check your work. Correct any improper configurations. Nitrogen configuration: 1s 2s 2p 2 2 3 Oxygen configuration: 1s 2s 2p 2 2 4 Fluorine configuration: 1s 2s 2p 2 2 5 Neon configuration: 1s 2s 2p 2 2 6 9. Apply: Atoms are most stable when their outermost shell is full. If their outermost shell is not full, atoms tend to gain, lose, or share electrons until the shell fills up. While doing this, atoms react and form chemical bonds with other atoms. Based on this, what can you infer about the reactivity of helium and neon? Helium and Neon are unreactive 10. Think and discuss: Select the PERIODIC TABLE tab, and look at the second row, or period , of the table. How does this row reflect the subshells of the second shell? There are two subshells in the second shell, the s and the p. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Activity B: Atomic radii Get the Gizmo ready: ● On the PERIODIC TABLE tab, select Na (sodium). ● Select the ELECTRON CONFIGURATION tab. Question: How do the radii of atoms change across a period of the periodic table? 1. Predict: Positively charged protons in the nucleus of an atom are attracted to negatively charged electrons. How do you think the atomic radii will change as electrons are added to a shell? It will increase 2. Arrange: Create a proper electron configuration for sodium. After clicking Check , note the Electron configuration and the Atomic radius now listed at right. Sodium electron configuration: 1s 2s 2p 3s 2 2 6 1 Atomic radius: 190 picometers 3. Compare: Click Next element , and then add an electron to the magnesium atom. Click check, and record the electron configuration and atomic radius below. Magnesium electron configuration: 1s 2s 2p 3s 2 2 6 2 Atomic radius: 145 picometers 4. Gather data: Create electron configurations for the next six elements. Record the electron configuration and atomic radius of each. (Note: The symbol for picometer is pm .) Element Number of electrons Electron configuration Atomic radius (pm) Aluminum 13 1s 2s 2p 3s 3p 2 2 6 2 1 118 pm Silicon 14 1s 2s 2p 3s 3p 2 2 6 2 2 111 pm Phosphorus 15 1s 2s 2p 3s 3p 2 2 6 2 3 98 pm Sulfur 16 1s 2s 2p 3s 3p 2 2 6 2 4 88 pm Chlorine 17 1s 2s 2p 3s 3p 2 2 6 2 5 79 pm Argon 18 1s 2s 2p 3s 3p 2 2 6 2 6 71 pm 5. Analyze: How does the atomic radius change across a period of the periodic table? It decreases 6. Interpret: Select the ATOMIC RADIUS tab. What do you notice? As the protons increase, the atomic radius decreases. The difference is significant between Na, Mg and Al Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

Activity C: The diagonal rule Get the Gizmo ready: ● On the PERIODIC TABLE tab, select Ar (argon). ● Select the ELECTRON CONFIGURATION tab. ● Turn on . Show number of electrons Question: How are the electron configurations of elements beyond argon determined? 1. Arrange: Create the correct electron configuration for argon. Then, click Next element to get to potassium (K). Click once in the first 3d orbital, and then click . Check What feedback is given? Electrons not placed in correct energy levels 2. Rearrange: The 4 s subshell is a lower-energy subshell than 3 d , so it is filled first. Remove the electron from the 3d orbital and place it in the . (Note: For simplicity, all but the outer shell 4s orbital. Click Check electrons will disappear on the Bohr Model .) Is this configuration correct? Yes What is the configuration? 1s 2s 2p 3s 3p 4s 2 2 6 2 6 1 3. Arrange: Click Next element and add an electron for calcium. Click . Check What is the electron configuration for calcium? 1s 2s 2p 3s 3p 4s 2 2 6 2 6 2 4. Arrange: Click Next element and add an electron for scandium. Try different orbitals until you find the right one. What is the configuration for scandium? 1s 2s 2p 3s 3p 4s 3d 2 2 6 2 6 2 1 5. Observe: Scandium is the first element to contain electrons in the d subshell. How many orbitals does the d subshell have, and how many electrons can fit in the d subshell? 5 orbitals, 10 electrons 6. Infer: Select the PERIODIC TABLE tab. The middle section of the table contains ten groups that make up the transition metals. Why do you think this section is ten columns wide? because there are 5 orbitals in the d shell and each orbital contacts 2 elects. 2 x 5 = 10 Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved

7. Observe: Select the ELECTRON CONFIGURATION tab. Make sure the subshells are ordered by Energy , which will arrange them from lowest to highest energy, bottom to top. Based on what you see, in what order do you think subshells will be filled? 1s 2s 3s 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p 8. Make a rule: Next to Subshells ordered by , select . Number The diagonal rule at right shows which subshell will be filled next. To follow the rule, move down along an arrow until you reach the end of the arrow. Then move to the start of the next arrow to the right. A. Which subshell is filled after 4 ? p 5s B. Which subshell is filled after 6 ? s 4f C. Which subshell is filled after 5 ? d 6p 9. Practice: Determine the electron configurations of the following elements. Use the Gizmo to check your work. (Note: In some cases, the diagonal rule doesn’t work perfectly. If you submit a theoretically correct configuration, the Gizmo will give you the actual configuration.) Element Atomic number Electron configuration Cobalt (Co) 27 1s 2s 2p 3s 3p 4s 3d 2 2 6 2 6 2 7 Germanium (Ge) 32 1s 2s 2p 3s 3p 4s 3d 4p 2 2 6 2 6 2 10 2 Neodymium (Nd) 60 [Xe] 4f 6s 2 Gold (Au) 79 [Xe] 4f¹ 5d¹ 6s 1 10. Infer: Select the PERIODIC TABLE tab. Earlier you saw that the transition metals represent the filling of the d subshells. Now locate the purple lanthanides and actinides on the bottom rows of the periodic table. A. How many elements are in the lanthanides series? 14 B. Which subshell is represented by the lanthanides series? 4f C. Which subshell is represented by the actinides series? 5f D. In general, how does the shape of the periodic table relate to electron configuration? It shows electrons filling shells Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved